The network info/connection protocol.

It is used to find Quake servers, get info about them, and connect to them.

Once connected, the Quake game protocol (documented elsewhere) is used.

General notes:

game_name is currently always "QUAKE", but is there so this same protocol
    can be used for future games as well; can you say Quake2?
 
CCREQ_CONNECT
    string  game_name               "QUAKE"
    byte    net_protocol_version    NET_PROTOCOL_VERSION
 
CCREQ_SERVER_INFO
    string  game_name               "QUAKE"
    byte    net_protocol_version    NET_PROTOCOL_VERSION
 
CCREQ_PLAYER_INFO
    byte    player_number
 
CCREQ_RULE_INFO
    string  rule
 
CCREQ_RCON
    string  password
    string  command
 
 
 
CCREP_ACCEPT
    long    port
 
CCREP_REJECT
    string  reason
 
CCREP_SERVER_INFO
    string  server_address
    string  host_name
    string  level_name
    byte    current_players
    byte    max_players
    byte    protocol_version    NET_PROTOCOL_VERSION
 
CCREP_PLAYER_INFO
    byte    player_number
    string  name
    long    colors
    long    frags
    long    connect_time
    string  address
 
CCREP_RULE_INFO
    string  rule
    string  value
 
CCREP_RCON
    string  reply

Note

There are two address forms used above. The short form is just a port number. The address that goes along with the port is defined as "whatever address you receive this reponse from". This lets us use the host OS to solve the problem of multiple host addresses (possibly with no routing between them); the host will use the right address when we reply to the inbound connection request. The long from is a full address and port in a string. It is used for returning the address of a server that is not running locally.